Construction and Optimization of the Ecological Security Pattern of Xishuangbanna Based on Fragmentation Index

Tropical forests are considered the most abundant source of biodiversity in the terrestrial ecosystem and the key to international biodiversity conservation. Due to the rapid process of urbanization and land conflicts, regional ecological security is under tremendous pressure, resulting in biological habitat destruction, ecosystem service degradation, biodiversity reduction, etc. Consequently, the construction and optimization of ecological security patterns can improve ecological environment stability, restore ecological function, and protect biodiversity, which is an important spatial way to solve regional ecological environment problems and improve regional ecological security. In this study of Xishuangbanna, Yunnan Province of China, ecological sources were obtained through ecological system service and ecological sensitivity comprehensive superposition, followed by ecological source extraction through hot spot analysis. The resistance coefficient was modified on the basis of the land cover type through landscape fragmentation comprehensive index construction, and Linkage Mapper calculation was performed to calculate ecological corridors and nodes with the ArcGIS cost-distance analysis module to construct and optimize the ecological security pattern in the Xishuangbanna area. The main results are as follows: (1) Twenty important ecological source areas were extracted from the Xishuangbanna area, covering a total of 7,709.56 km2 and accounting for 40.33% of the study area. The coincidence rate with the existing nature reserves is 89.92%, which is mainly distributed in natural reserve areas, such as the northern part of Jinghong City, Central and southern parts of Mengla County, and the southern part of Menghai County. (2) Compared with the resistance surface corrected by night light data, the spatial differentiation of the landscape resistance surface corrected on the basis of landscape fragmentation is more significant. Among this, the identification of ecological corridors, the spatial distribution of the corridors, the reduction of conflict points of human activities, network connections, and optimal corridor verification delivered relatively better results. (3) The ecological corridor, which includes the key corridor and the potential corridor of 278.59 km and 631.73 km, respectively, shows a spatial pattern combined with the half ring and the small rings. Moreover, the ecological nodes include 20 resource strategic points, four ecological strategic points, 27 ecological temporary rest points, and 24 ecological fracture points. (4) By referring to the ecological security patterns of Xishuangbanna area, the layout of the ecological spatial structure was optimized as "one belt, one corridor, and four groups." "One belt" was the ecological river corridor belt with the Lancang River as the main axis and the tributaries on both sides. "One corridor" refers to the central corridor structure connecting the national nature reserves of Mengyang, Naban River, and the Mangao Nature Reserve. Based on the existing nature reserves, the four groups were divided into the Bulong-Mangao nature reserves, Menglun three sub-reserves, Mengla-Yiwu-Mengyang-Menglun nature reserves, and Mengla-Shangyong nature reserves. This study provides a practical case for formulating ecological and environmental protection in Xishuangbanna.